1. Field of the Invention
The present invention relates to cosmetics, a N-acylamino acid composition, a novel N-acylamino acid and a derivative thereof. More particularly, it pertains to cosmetics which comprise a N-acylamino acid and/or a derivative thereof and which have excellent hair growth promoting effect, humectant action, subcutaneous blood flow rate increasing action and the like and thus are well suited for hair growth, skin care and the like; a N-acylamino acid composition which has excellent surface active action, disinfecting action, metal corrosion inhibiting action, etc. and thus is particularly useful as a detergent, dispersant, emulsifying agent, antimicrobial drug, antiseptics, ultraviolet absorber and the like; a N-acylamino acid, a salt thereof and an ester thereof being favorably used in the aforesaid purpose of use.
2. Description of the Related Arts
Cosmetics blended with various effective drugs have heretofore been known. For example, a hair growth agent is incorporated with, as effective drugs, a vitamin such as vitamin E; a vasodilator such as acetylcholine derivatives; an antiflammatory agent such as lithospermum root extract; female sex hormone such as elastodiol; a skin function enhancing agent such as cepharanthine; a melanin synthesis catalyst such as copper pantothenate; a keratolytics such as salicylic acid; and the like, said hair growth agent being used for the prevention and therapy of alopecia.
As an example in which a fatty acid or a derivative thereof is blended in cosmetics such as a hair growth agent, an example is known in which a natural vegetable oil such as olive oil or castor oil or stearic acid is blended for the purpose of improving the physical properties of a product. It is known that almost all of fatty acids which constitute various lipids of natural origin such as vegetable oils and animal oils is a fatty acid having even-numbered carbon atoms chain, whether the fatty acid is a saturated one such as stearic acid, palmitic acid, etc, or an unsaturated fatty acid such as oleic acid, linolenic acid, etc.
On the other hand, examples in which a fatty acid having odd-numbered carbon atoms or a derivative thereof is incorporated in hair cosmetics include the compound described in Japanese Patent Publication No. 41363/1988.
However, although it is said that the above-mentioned conventional cosmetics such as the hair growth agent are effective for the prevention and improvement of dandruff, itch, hair falling out and the like and besides promote hair generation and restoring, the real situation at the present time is that cosmetics which exert satisfactory effect have never been realized.
As a typical amino acid-based surfactant, there is known a group of N-acylamino acids that are obtained by the condensation reaction of amino acids and fatty acids. The aforesaid N-acylamino acids are imparted with a variety of functions such as high safety for environment and ecology, affinity for skin and hair, special association formation originating from the amide groups, chelate function and antioxidizing function, whereby they are expected to find a wide variety of application by making use of such characteristics.
There have heretofore been reported, as such N-acylamino acids, N-acylamino acids that are obtained by the condensation reaction of natural fatty acids and amino acids. As mentioned hereinbefore, almost all of the natural fatty acids, that is, the fatty acids which constitute various lipids of natural origin such as vegetable oils and animal oils is a fatty acid having even-numbered carbon atoms.
On the other hand, examples in which a derivative of a fatty acid having even-numbered carbon atoms such as a N-acylamino acid salt is blended in a detergent include the compound described in Japanese Patent Application Laid-Open No. 42809/1972.
However, the compositions comprising the above-mentioned conventional N-acylamino acid, although proposed to be applied to various uses such as a detergent, are still insufficient in surface active action, etc. thereby bringing about the actual circumstance at the present time that a composition which exhibits satisfactory effect has not yet been obtained.